I want to get this value using the linkbutton that was inside the gridview to display the modal

<pre><divid="id01"class="modal"><formclass="modal-content animate"><divclass="imgcontainer"></div><spanonclick="document.getElementById('id01').style.display='none'"class="close"title="Close Modal">×</span><divclass="container"><p> This message was rejected by the recipient email system. Please check the recipient's email address and try resending this message, or contact the recipient directly</p><p> A problem occurred while delivering this message to this email address. Try sending this message again. If the problem continues, please contact your helpdesk.</p><p> The domain name in the email address is incorrect. Check the address.</p><p> Sorry, I couldn't find any host named like(Sample@email.com). Please check the email address and try again.</p><p> The server has tried to deliver this message, without success, and has stopped trying. Please try sending this message again.<br/> If the problem continues, contact your helpdesk.</p><buttontype="button"runat="server"onclick="document.getElementById('id01').style.display='none'"id="btncancel">Cancel</button><br/><asp:Labelrunat="server"ID="lblError"></asp:Label></div></form></div>

and here's the code of the gridview

<pre><formid="form1"runat="server"><div><asp:GridViewID="GridView1"runat="server"AutoGenerateColumns="False"BackColor="White"BorderColor="#CC9966"BorderStyle="None"BorderWidth="1px"CellPadding="4"OnRowCommand="GridView1_RowCommand"OnSelectedIndexChanged="GridView1_SelectedIndexChanged"><Columns><asp:TemplateFieldHeaderText="Subject"><ItemTemplate><<pre><asp:LinkButtonID="LinkButton1"runat="server"CommandArgument="EmailDetails"CommandName="DisplayEmail"Text='<%# Eval("Subject") %>'></asp:LinkButton><%--<asp:BoundField DataField="Subject" HeaderText="Subject Email" />--%><asp:BoundFieldDataField="Sender"HeaderText="Receiver"/><asp:BoundFieldDataField="DateCreated"HeaderText="Date and Time Sent"/><asp:BoundFieldDataField="DateReceive"HeaderText="Date and Time Received"/><asp:BoundFieldDataField="EmailHeader"HeaderText="Details"/><FooterStyleBackColor="#FFFFCC"ForeColor="#330099"/><HeaderStyleBackColor="#990000"Font-Bold="True"ForeColor="#FFFFCC"/><PagerStyleBackColor="#FFFFCC"ForeColor="#330099"HorizontalAlign="Center"/><RowStyleBackColor="White"ForeColor="#330099"/><SelectedRowStyleBackColor="#FFCC66"Font-Bold="True"ForeColor="#663399"/><SortedAscendingCellStyleBackColor="#FEFCEB"/><SortedAscendingHeaderStyleBackColor="#AF0101"/><SortedDescendingCellStyleBackColor="#F6F0C0"/><SortedDescendingHeaderStyleBackColor="#7E0000"/><asp:Labelrunat="server"ID="lblSubject">